Process of making lubricating oil



, July 7, 1931. w. T. BRYANT PROCESS OF MAKING LUBRIGATING OIL FiledAug. 30, 1927 Patented July 7, 1931 'narran STATES PATENT OFFICEWILLIl-LM T. BRYANEOF I.|IO`'S'I[O1\T,y TEXAS, ASSIGITOR T0 W.- A.WILLIAMS, OF HOUSTON,

. .TEXAS PROCESS OFIv'IAKING LUBRICATING OIL Application filed August30, 1927. Serial No. 216,497.

The present invention relates to a process of manufacturing lubricatingoils, and has particular application to the production of oils suitablefor lubrication from asphalt or naphthene base crudes. i

It is an object of the invention to utilize as much ofthe heavyfractions as possible, since it has been established that the socalledbottoms are highly valuable for lubricating oils.

To this end, the inventioncontemplates but a single completedistillation of the crude thereby materially lessening the apparatusemployed andshortening-v the time of operation, both vas regards theproduction of the distillate and its subsequent chemical and mechanicaltreatment.

The generally accepted method of refining an asphalt or naphthene basecrudefor the production of lubricating oils consists in distilling thecrude and separating the desired fractions. The various lubricatingfractions are then redistilled in order to obtain the desired flash andviscosity. The lubricating fractions obtained during the process ofredistilling that do not have the desired flash and viscosity arecollected and further refined by reducing or blending with otherproducts. On the redistillation of the lubricating distillate thegenerally accepted practice is to add aV weak caustic solution to thelubricating distillate during the proc- *ess of the second distillation.After the lubricating distillate is redistilled and the desiredfractions obtained, the product is then transferred to the agitator forchemical treatment. The chemical treatment consists of first agitatinfrthe distillate with a fixed charge of 66 Be., sulphuric acid. Thepurpose of the weak acid treatment is 'to remove any water that iscontained within the distillate. After the acid and the acid sludgeproduced from this treatment are removed, the charge is further .treatedwith a much stronger acid, -usually a powerful acid as a fumingsulphuric acid of substantially 98% concentration, and upon the removalof the acid sludge produced from this y treatment, the chargeis thentransferred to .a wash agitatorrwhere the remaining acid and preferablythe former. ,then passed to a wash agitator, and may, if desired, betreated with a weak caustic, and

held-by the distillate is neutralized with a weak caustic soda or a sodaash solution. After the excess caustic solution is removed, thedistillate is transferred to a blow bright tank where the traces ofmoisture held by the distillate is removed by blowing with air.

This process is objectionable, because in the first distillation, a baseof to 10% remains, which base is generally employed as fuel oil, and onredistillation of the lubricating distillate', it is necessary to leavea base of from 5 to 8% which is utilized also for fuel-purposes. Thus,anywhere from to of the crude and particularly thatpart possessing morevaluable lubricating qualities is lost.

The figure is a fiow sheet illust-rating the process.

In this figure, A is the still wherein the crude oil is run, and whereagitation with steam 4in the presence of caustic takes place. The gasoil and other fractions are drawn oflil and the remaining residue isdistilled overhead and collected in the chamber C. From the chamber C,the residue is run into the reduction still B, where the oil is giventhe desired viscosity and flashpoint, and lighter fractions are removed.The dry distillate is then run into the chemical agitator F, whence itis subjected to acid treatment with either 66 B. or stronger usually Thematerial is the excess caustic is removed and the chemically treated oilis passed to an air blower In some cases, the air blower I-I is notemployed, and the oil is passed to a clay treating tank I, and thence toa filter J, from which the oil may be passed continuously to a vacuumapparatus to get out any remaining water. Y

With the present invention, I have found that the final product of myprocess is a lubricating oil of relatively light color possessing adistinct greenish fluorescence free from bluish tints, and furthermore,I do not iind it necessary to blend my product with a second distillatein order to secure the desired light color. My process is also icharacterized by the fact that the unsaturated hydrocarbons can beremoved Without interference With the cyclic or naphthene ringcompounds, and my improved oil is particularly free fromhthe emulsifyingconstituents 'preventing any p'ossibility vef the emulsificationoccurring 'uri'rig treatment With chemicals. y a$result,of testsconducted with my product, it is found to be stable and highlyresistantto heat, due to the fact that the lubricating oil issubstantially free *from organic acids, resins, sulfo-acids, unsaturatedhydrocarbons vvhi'clr-areeasily ii'zfif dized, gum Iand phenols Whichare apparently cony tedjintoallaline,stable products ryi are o 'giefareuueeroe `ehren I emp-roy, sedation are left Benina part or' ureas'e.

Aside trom-ure feet that I do not plateale 'al doiuuedistillation,einverti- Vtion dut "in its `subsequent` 'ste meenemen 1th "materiallyexpense' and tiere', and ehereeulfoeift fp o ld'in'ltlrquant yairdqualtydrcate's ps of chemical less Inearryngeut die process, the Crude oil tose --aisunea Winoo may be any aes-a1 crude, is charged intol a` stilland 'agitated as for eXar'ple, applying Ythe bottom thereofnas 4is Wellknown." D"i'i1'"-ing` taieagaeuoo, there le eee-lieu feo 'jure orioJvWea-l: 'caustic solution h is preferably 'gradually ira;ouuaed.v desmay be employed one t 'conducted vvith My pref cev for employing acaustic suoli essor hydroxide fie the re-Sau of emmene wherein aeee"foorraueaeeuen Y bases 'as oeroude hydroxide, iiynjectedft'odistillation, Vwith agit-Mien l f the materiel are y pife'vii'o'usly,described are einlesen is eootafoea: anni an -oif the on 'hee beenaieaueaovei teje-a with the fea'ee'ption-fepossi-blyof bottoms; o v- Thesmall @enables the vprocess 'to heV carried et ure pro'oee's highlyfeaieieae errepercentage of bottomsl yis pumped from the still andutilized for fuel purposes. v

The entire lubricating fraction is collected and transferred to a tankor still for reducing the oill and obtaining the desired flashviscosity,

T'lie'reduction process :comprises heating the 'oilto remove the lighterfractions Which arevdistilled over head -until the remaining base orycharge meets the desired test.

In this manner, no redistillaticn With consequent apparatus-extensiveheat and loss of time is employed, and the flash and vis- `csity ofthelubricating stock may be easily controlled. For example: a viscosity of200 vflash of 325 Fahrenheit lcan be fobtaihfed tvith ve'r'y'lit'tlfereduction; Un fur`- 'ther redti'ct'io'nf vvith tlf'r'eV percentage Y'ofvthe K products distilled/off, it is' "pos's'ito 'obtain in 'this simplemanner 'a base g for exemple-greater vvejeoeayjf ena M A fl sh tV a:considerable range, as reati-area. o l v lt'will be here noted that the`entire vbase not-tonly tvitlhit its iedi'sftiillation, aout also ywithout ire-eeen@ of blending. TVlYentliis' base' has been reduced 'tothe sird viscosity "and"i'faslr,l lit is transferred to aleareafbieaviator roi chemical aoeuoefa. ,5 tthispint, it Ais thought vv'ell to'explain that the caustic lrasldeen present in 'the oil all-'theoperations 'prefvious'ly described, arid 'While possibly some of it maylijafe b'een'losttlis has been found not yto Wciably effect 'theoperation of the .0f lighter. 'er

*easnof yfthe,presence of caustic in the rouaeea drainage', i nopermitted oo employ *atveall lacid treatment and I prefer to treat the(distillate with `66 Be., sulphu'ric acid.

` sinformer,processes, an initial tn'ent tvith 66 Be., 4aeidisnecessar'y as a p I` nate this step since the distillate deliveredtoftlre 'agitator lchemjicalftaiil; ris *substantially dry. Y l Qlhilleil erply 'preferably a Wealr acid 'treatiiifen' using va'sufliientiduaritity of acid dependentup'on ithe viscosity 'and quality of 'thedistillate'being treated, I 'have in some L "cases -used stronG-rrVacid'of 98%. How fever, 'for mostpur @ses 4the Vweaker acid has beencompletely effective ingproducing an oil having the desired 'quality andcolor. v

After they distillate has been subjected to llt) withdrawn, iene"distillate is traae'lferreol to e jsuitobiejvasu agitar-or there dieaard heid by the diedi-laters neutralized with freak solution or eaustiesode ash if le, "fourfdfaefefeeeary- Y j It, shout negocia-fedelta one'reduced distinte produ'eed ,distillation "or the caust v'crude inayllfeincre treated in the 'agitator and 'wat ieee 'iirenuooa of eeeemulsiication than is the case With processes heretofore employed. Theexcess caustic is then removed and r the distillate is transferred to arather ,low

exchanger Where it is subjected to a temperature sufficient to raise theoil to a point Where it vvill react with, a decolorizing agent.

. The heated oil at such temperature is passed to a-mixing tank and adecolorizing clay is added While the mass is agitated and the reactiontemperature'of the oil is sustained by means of heating elementsarranged in the mixing tank. Since reaction takes place at once betweenthe oil and clay, the oil may be immediately filtered so that theprocess is. very rapid and r'can be conducted with a"v minimum ofcomplicated apparatus jand lWithout any loss of time.

The' filter is preferably of a type wherein the deposits can be flushedor sluiced from the chambers by means of Water, Without requiringdismantling of the iilteringapparatus. yThe employment of such a filteravoids the usual delays incidental to taking Vdown the apparatus toremove the cake and v then assembling. By using a filter from ,Which thecake is sluiced off by streamsof Water, my process is rendered so tospeak continuous andv the time ofoperations is materially reduced. Asmall quantity of Water will pass through With the oil and since the oilis at a temperature aboveboiling, the Water content may beV easilyremoved by vacuum treatment.

As previously stated, application ofthe caustic solution to the crudeprior to distillation, permits the useiof relatively Weak sulphuric acidinthe chemical treatment,

and Whereas Without the addition of this caustic, it Would be necessaryto employa vmore powerfutacid as fuming sulphuric acid of substantially98% concentration.

lVhen the distillate is treated withV G6'B.,

acid and subsequently clay treated, the desired greenish yiuorescenceisvery pronounced While treatmentivith 98% acid or stronger, does not`result in so defini-te a greenish cast.

The bluish` tint usually found in the distillate is entirely absent frommy product,

4and I attribute this to `the usefof caustic Within the crude during theperiod of distillation, experiments having shown Vthat Without the useof caustic, a very pronounced bluish fluorescence isv produced. AItisfrfur-y ther desirable to employ a Weak acid treatment in accordance.With my process, since I have found that the distillate can be furtherrefined by means lof clay Without first neutralizing With caustic sodaor soda ash .tarry matter commonly called acid sludge.

This is due to the fact by my process the unsaturated hydrocarbons areremoved Without interference With the cyclic or naphthene ringcompounds.

The presence of the naphthene ring compounds is obviously a verydesirable feature, and is primarily the result of'the relatively lightacid treatment to which the oil is subjected.

By introducing a small amount of weak caustic into the crude andagitating the mass prior to Vsubjecting the oil to distillation, I findthat various organic acids, resins, phenols, sulfo-acids are convertedinto stable alkaline products by distillation and remain behind as partofthe bottoms.

In treating the crude With caustic and then heating and distilling totemperatures as high as 675 Fahrenheit and 700o Fahrenheit, thenaphthenic acids and other organic acids are neutralized and as stated,stable alkaline products such as sodium salts are formed by reactionWith the nitrogenuous and oxygenated bodies present.

I have tested the product produced in the above manner, and find thatthe oil is stable at high temperatures. For example, a qua-ntity of thefinished oil has been subjected to a temperature of substantially 300Fahrenheit more or less for a considerable length of time Withoutmaterial cha-nge either in color or quality.

It Will be understood from my process that the percentage of bottomsWhich is lost in the single distillation as Well as the percentage of`sludge Which is lost in the acid treatment is very low, and since it hasbeen definitely established that the so-called bottoms obtained duringthe refining process of a lubricating oil contain the most valuablelubricant, the importance of my improvements can be readily seen.

Furthermore, by using a Weak sodium hydroxide solution, or other causticsolution,

there seems to be an increased tendency of vthe oil not to crack at thehigher tempermoved by Washing.

My process is furtherr characterized by the fact that air-.is excludedso that no oxidized il? i 'there is no 'lossof'cri'ifde by reason "tionVof voil and f'saii'stic liquor.

' of the oil. With a strong solution, it'vvould vbe almost impossible toobtain 'a `clean cut Vsepai"ation of the oil andv alkaline solution.'Moreover, by usine` a Weak :caustic solution, the percentage ofobjectionable products, such as soaps amount. f

If la' strong caustic 'solution Were used,

V'there is a possibility of the entire ``charge emul'sifying -Which isdifficult to break, often requiring a separate distillation. With'myprocess 'employing a Weak caustic :solution during heating anddistillation,

of separa- Moreover', no emulsification takes place and `there islno'loss 'due togsuch reaction. I also find that when 'subjected' tofurther chemical treatrne'ii't, the possibilities vof emulsica'tion Vofthe distillate is reduced to a minimum.

It will be observed that the use of complil cated apparatus is reducedsince no double effect in 'the 'cost of 'production and my in-`distillation is necessary and 4the neutralizing step inthe chemicaltreatment may be eliminated. Moreover, the initial alkali treatment iscarried on Without lany additional apparatus.

The time of operations for conducting my process is materially reduced,and this, of course, is a very important item.V

Both time 'and apparatus for y'have their vention verymateriallyreduc'es the expense of refining "as will be quite clear.

Bythe fuse of the improved method of refining lubricating oil, a producthaving a green cast can be produced, and Aalso a Vred oill having ragreen fluorescence can befohtained There is but a single'ldistill'ation'and no necessity ofbl'ending when Voperating in 'accordanceWith myprocess. Also, it should be borne lin mind that Athe treatment hereindescribed results in a very high Yield 'olfexeent qualify lancering 0aet 'a relatively vsmall cost and SWithiria time 'period vvhich has beenmuch shortened over Athe present accepted methods.

necesi er @green 'Casi intra-atie@ en,

isreduced to an inappreciable A Y 'my hand. i It Will be understood thatYWhere theusu'a'l processes l having for their; purpose thepr'otuatethellcast, my process-'gives a uniform product of green cast for bothred and pale "oils Without further treatment. v

Blending of bottoms from `cracked fuel with a distillate is 'oneartificial expedient, Whilethe 'use of bright vstock is another. Suchadditional-treatments are enormousily erpensive from the standpoint ofoperation, but have heretofore been necessary'to vgive the oil thedesired color and render it marketable. Y

My process obviates this and not only shortens materially time of`operation and cost of blending material, but actually utilizes themajorpart of the bottoms Which Yare considered the valuable constitutentand Were hertofore generally unused in the direct vrefining treatment.By using "a caustic crude and following the steps heretofore outlined,my process gives'a clear product having a- 'percepticle and stablegreenish cast.A i

I claim:` v

l. The process of refining oil vvhich coinprises introducing the oilinto a still, adding a smallv quantity ofVv dilute, caustic, all- Akalisolution thereto, distilling'off the lighter fractions, continuingdistillation of the remaining charge of Vcaustic and oilY untilsubstantially live percent of bottoms remain,

reducing said last mentioned distillate by heating to V remove lighterfractions only, subjecting the reduced distillate to a vchemicaltreatment vvith acid of less than ninetyveight percent concentration,removing the .f

sludge, treating With absorbent clay to decolorize the oil, ltering theVoil, and subjecting the oil Vto la brightening treatment.

2. The process of refining oil' which comprises introducing the oil intoIa still, adding .1 `a small quantiyfof dilute,-

caustic, alkali solution thereto, Vdistilling off the lighter Yfractions, continuing 'distillation of the remaining charge of causticand oil until 'substantially Vfive percent of bottoms remain, reducingsaid last mentioned distillate by heating to remove lighterV fractionsonly,

subjecting Vthe reduced distillate to a chemical treatnient W'ith yacidof less than ninety- `eight percent concentration, vremoving the sludge,heating the distillate to reaction temperature-With a decolorizingagent, introducing a decolorizing agent into the distillate vv'hen 'thelatter is at sucha temperature that the agent Will immediately react,

continuously filtering to separate the oil and "agent, and subjectingthe filtered distillate,

While still-in heatedy condition', to a vacuum treatment.

' In testimony vvlier'eof I have hereunto set WILLIAM T.- 'BRYANT.

prey-'artificial mener acqui-'re and aeoen- Egli

